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From "Michele Mase'" <michele.m...@gmail.com>
Subject Re: [users@httpd] Unable to fork new process
Date Wed, 25 Jan 2017 10:29:34 GMT
There is the possibility of a memory leak: following an old post about the
same problem https://ubuntuforums.org/showthread.php?t=1505539, I tried the
experiment: using the php script to keep reloading apache until apache logs
an error (a simple loop that reloads apache), after 100883 reloads and 7621
seconds, the apache on the test machine hangs with the error "[error]
(12)Cannot allocate memory: fork: Unable to fork new process".
Notice that the test machine is absolutely empty, there is only the web
server with no activity.
On a medium/large prod. environment, some apache reload (due to config
change, like add or remove a virtualhost) together with the load of the web
sites causes the same error after some days. It seems to be like the
following algorithm: xx apache reloads + yy load average = zz time memory
leak.
I applied the sipliest solution:
changing the logrotate.d/httpd by replacin service httpd reload with
service httpd restart
But the memory leak stirr remains.
Any better suggestion? Anyone ever will correct the httpd code?
Best regards

On Tue, Jan 24, 2017 at 9:52 PM, Houser, Rick <rick.houser@jackson.com>
wrote:

> Where and what is the leak?  If it’s in the workers (the parts running as
> non-root), perhaps just set a request limit so they keep cycling out
> automatically within Apache and getting replaced seamlessly with new
> children?  If it’s in the higher level processes (the root owned ones),
> that’s not going to work.  I could be mistaken, but I thought a process or
> thread limit also gave a message similar to that, so double check your
> ulimit settings.  Adding memory not helping you further implies you are
> running up against a software limit of some kind.
>
>
>
>
>
> Rick Houser
>
> Web Administration
>
>
>
> *From:* Darryl Philip Baker [mailto:darryl.baker@northwestern.edu]
> *Sent:* Tuesday, January 24, 2017 14:08
> *To:* users@httpd.apache.org
> *Subject:* RE: [users@httpd] Unable to fork new process
>
>
>
> First I am assuming you are using the Red Hat distributed version. Is
> upgrading to Apache httpd 2.4 from the Red Hat Software Collection an
> option?
>
>
>
> I can think of several options to detect and automate the restart as a
> remediation. One would be to script a memory watcher using the free command
> and automatically executing the restart steps you do manually. The run the
> script out of cron every 5 minutes.
>
>
>
> For a fix you might want to peruse the release note for Apache versions of
> 2.2 after 2.2.15, and the mods, for memory leak fixes and see if Red Hat
> has backported them into their version. If you find one that wasn’t
> backported time to nudge Res Hat. Maybe someone on this list more in tune
> with the releases can point you at one or two of these.  Or just build a
> newer version of Apache 2.2 from source
>
>
>
> Darryl Baker
>
> NIT - CI -DAPS
>
> X76674
>
>
>
> *From:* Michele Mase' [mailto:michele.mase@gmail.com
> <michele.mase@gmail.com>]
> *Sent:* January 24, 2017 12:10 PM
> *To:* Httpd Users List <users@httpd.apache.org>
> *Subject:* [users@httpd] Unable to fork new process
>
>
>
> All,
> I've a apache web server with 600 web sites as reverse proxy. The average
> of req. is more than 100 req/sec during all the day.
> The apache is a 2.2.15 release 56.el6_8.3 (RedHat 6.x system up to date) +
> mod_ssl.
> Every 10 days, the system has problems, and in the error log i found dozen
> of:
>
>  [error] (12)Cannot allocate memory: fork: Unable to fork new process
>
> The temporary solution for me is the following: after an alert mail from
> the system monitoring server, I must restart the httpd using:
>
> service httpd stop; killall httpd.worker; killall -9 httpd.worker; service
> httpd start
>
> Adding more ram to the system does not help.
>
>
>
> Any suggestion?
>
> Best regards
>
> apachectl -l
> Compiled in modules:
>   core.c
>   worker.c
>   http_core.c
>   mod_so.c
>
> apachectl -M
> Loaded Modules:
>  core_module (static)
>  mpm_worker_module (static)
>  http_module (static)
>  so_module (static)
>  log_post_module (shared)
>  evasive20_module (shared)
>  auth_basic_module (shared)
>  auth_digest_module (shared)
>  authn_file_module (shared)
>  authn_alias_module (shared)
>  authn_anon_module (shared)
>  authn_dbm_module (shared)
>  authn_default_module (shared)
>  authz_host_module (shared)
>  authz_user_module (shared)
>  authz_owner_module (shared)
>  authz_groupfile_module (shared)
>  authz_dbm_module (shared)
>  authz_default_module (shared)
>  ldap_module (shared)
>  authnz_ldap_module (shared)
>  include_module (shared)
>  log_config_module (shared)
>  logio_module (shared)
>  env_module (shared)
>  ext_filter_module (shared)
>  mime_magic_module (shared)
>  expires_module (shared)
>  deflate_module (shared)
>  headers_module (shared)
>  usertrack_module (shared)
>  setenvif_module (shared)
>  mime_module (shared)
>  dav_module (shared)
>  status_module (shared)
>  autoindex_module (shared)
>  info_module (shared)
>  dav_fs_module (shared)
>  vhost_alias_module (shared)
>  negotiation_module (shared)
>  dir_module (shared)
>  actions_module (shared)
>  speling_module (shared)
>  userdir_module (shared)
>  alias_module (shared)
>  substitute_module (shared)
>  rewrite_module (shared)
>  proxy_module (shared)
>  proxy_balancer_module (shared)
>  proxy_ftp_module (shared)
>  proxy_http_module (shared)
>  proxy_ajp_module (shared)
>  proxy_connect_module (shared)
>  cache_module (shared)
>  suexec_module (shared)
>  disk_cache_module (shared)
>  cgi_module (shared)
>  version_module (shared)
>  unique_id_module (shared)
>  ssl_module (shared)
>  reqtimeout_module (shared)
> Syntax OK
>

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